Thursday, February 23, 2012

Propeller LCD and RTC work

Sorry for no updates for a while as I have been ill unfortunately.  Starting to feel better now however so I am back playing around with propeller.  I have a DS1307 real-time clock module (RTC) and the I2C LCD module from my Arduino beacon project that I have been wanting to get working.

The RTC was a complete no-brainer, it just works.  I plan to use it to allow atonomous operation of my beacons that need accurate time information such as WSPR.

The LCD however was a bit of a problem as I am not happy with the display drivers that are out there and have not found an acceptable I2C implementation for any display that I care for.

So, I ported the driver I was using for Arduino to spin and have it working now at least at a macro level.  I have not tested the functionality fully yet.  I am quite pleased with the initial performance.

The plan is to make a rather comprehensive driver that will work with either I2C or parallel mode, though I only will be using I2C.  Above you can see it driving my 20 character by 4 line display.  The I2C bit is implemented in the driver via bit-banging.  This allows the driver to be independent of any other I2C library.  The SDA and SCL pins can be specified with the default to share the I2C pins with the EEPROM.

On other fronts I am putting together a low pass filter module that uses six relay selectable low pass filters for the HF Bands 160 - 10 metres.  10 bands are covered with 6 filters.  Attenuation in the stop band should exceed -40dB.  I anticipate using an 8 bit I2C I/O expander, six bits of which will be used select the appropriate filter for the following bands: 160, 80, 60/40, 30/20, 17/15, 12/10 metres.  I anticipate using the remaining bits for transmit/receive switching and antenna auto-tuner control.  More to come on this.


  1. Hi Jeff. Hope you are feeling better.

    Will your LCD driver work with the Gadget Gangster LCD UI board (2 rows of 8 chars)? I'm not very happy with the standard one either.

  2. As long as the LCD controller is Hitachi HD44780 compatible (as most are), then it should work. Send me a link to the product you have and I will check it out.